• Gaia: the UI
• Gecko: the engine
• Gonk: all the rest
  

• Gaia apps are built with HTML, CSS and JavaScript
• Gaia developers use git
  
• Gaia code is at: https://github.com/mozilla-b2g/gaia/
• All FirefoxOS apps run on top of Gecko
  

• Gecko is written in C++, JavaScript and webidl
• Gecko developers use hg.
• Gecko code is here: http://hg.mozilla.org/mozilla-central
• Gecko runs on top of Gonk
  

• Gonk is developed in C and C++
• Gonk developers use github
• Gonk code is at https://github.com/mozilla-b2g/B2G
• And also in many other sub-repos https://github.com/mozilla-b2g

• Create accounts
• Install required software
  
• Clone FirefoxOS repos
  
• Join IRC and mailing lists

Much of what follows is derived from: https://github.com/bocoup/gaia-notes/blob/master/development-cycle.md

• Create an account on Github
• Create a Bugzilla account at https://bugzilla.mozilla.org/
• Each engineer should have their own accounts
• Once you have worked on the project long enough, you may be granted (or can ask for) commit rights so you can check in code.
  

• git and hg for source code version control
• Android Developer Tools, for the adb command for controlling phones over USB: http://developer.android.com/sdk/index.html

• gjslint: https://developers.google.com/closure/utilities/docs/linter_howto
• node.js: http://nodejs.org/
  

• git clone git://github.com/mozilla-b2g/gaia.git
• Or create your own fork on github and clone that.
• hg clone http://hg.mozilla.org/mozilla-central/ src
• git clone git://github.com/mozilla-b2g/B2G.git
• Follow directions in the README
  

• FirefoxOS developers use IRC channels #gaia and #b2g on irc.mozilla.org
• dev-gaia mailing list or google group
  
• dev-b2g mailing list or google group
• (The mailing lists may soon be integrated into a single list.)
• Communication also takes place in Bugzilla comments
• Github is used for code reviews, but not for discussions
  

• Product requirement ->
• User story ->
• Bugzilla bug ->
• Github pull request ->
• Reviews (technical, ux, security) ->
  
• Code checkin
• Close bug
  

• Use "add an attachment" to attach a patch (or link to a github pull request) to a bug
• Set the "r?" flag on the attachment to request review
• You must specify a reviewer
• "r+" means review granted
• "r-" means review denied: more work is required before the code can land.
• Check the "need more information" box at the bottom of the page to get another developer's attention
• Add "checkin-needed" to the Keywords field at the top of the page to request code landing when reviews are complete.
  

• https://developer.mozilla.org/en-US/Firefox_OS
• https://developer.mozilla.org/en-US/Firefox_OS/Platform
  

• https://developer.mozilla.org/en-US/Firefox_OS/Platform/Gaia/Hacking
• https://github.com/mozilla-b2g/B2G/blob/master/README.md
• https://wiki.mozilla.org/B2G
• https://bugzilla.mozilla.org/page.cgi?id=etiquette.html
• http://flailingmonkey.com/bugzilla-tips-hacks-and-etiquette